"It is a common superstition of mariners, that, in the high southern latitudes on the coast of Africa, hurricanes are frequently ushered in by the appearance of spectre-ships . . . the crew of these vessels are supposed to have been guilty of some dreadful crime, in the infancy of navigation; and to have been stricken with pestilence . . . and are ordained still to traverse the ocean on which they perished, till the period of their penance expire"